This invention relates to an apparatus for monitoring a closing process of a window pane, particularly a motor vehicle window pane, of a type having a sender and a receiver for electro-magnetic transmissions, having at least one light-deflecting mechanism which aids in transmitting electro-magnetic emissions from the sender to the receiver and with which operation of the window pane stops or is reversed if a transmission intensity received at the receiver changes during the closing process.
Such apparatus are known from the prior art and are used to prevent jamming or squeezing of body members or objects during the closing of a window that is driven by an electric motor.
In German patent document DE-PS 31 07 847, for example, an apparatus is suggested having a light conductor mounted along a closing, or upper, edge of a window frame which conducts light rays from a sender to a receiver. If the light conductor, which is constructed as a lightconducting fiber bundle, is squeezed, because, for example, an object is jammed between the window and the window frame, a change in the light intensity occurs at the receiver, thereby causing the motion of the window to stop or be reversed.
In another embodiment described in DE 31 07 847, the light conductor is constructed as a squeezable, plastic tube having a reflective coating on the inside.
Both embodiments have the disadvantage that manufacturing a monitoring apparatus of the described type requires a relatively cost-intensive and complicated light conductor.
It is even more disadvantageous that the light conductor has to be deformed for the monitoring apparatus to respond so that a response occurs only after an object or a body part has already been squeezed with a certain pressure.
Although a squeezing or jamming pressure required for activation of the monitoring apparatus is not very high, it causes an unpleasant sensation. A fright, or panic, reaction may also be possible. Squeezing may even result in injury, if, for example, body parts of children are involved.
It is an object of the invention to provide a monitoring apparatus which is particularly uncomplicated and cost-effectively constructed and which provides an influencing of a window drive without jamming or squeezing something.